Constituents of the Vietnamese medicinal plant Streptocaulon juventas and their antiproliferative activity against the Human HT-1080 Fibrosarcoma cell line

The methanolic extract of roots of Streptocaulon juventas, having shown strong antiproliferative activity against the highly metastatic human HT-1080 fibrosarcoma cell line, was subjected to activity-guided isolation to yield 16 cardenolides including five new ones, acovenosigenin A 3-O-\u3b2-digitoxopyranoside (1), digitoxigenin gentiobioside (2), digitoxigenin 3-O-[O-\u3b2-glucopyranosyl-(1\u21926)-O-\u3b2-glucopyranosyl-(1\u21924)-3-O-acetyl-\u3b2-digitoxopyranoside] (3), digitoxigenin 3-O-[O-\u3b2-glucopyranosyl-(1\u21926)-O-\u3b2-glucopyranosyl-(1\u21924)-O-\u3b2-digitalopyranosyl-(1\u21924)-\u3b2-cymaropyranoside] (4), and periplogenin 3-O-(4-O-\u3b2-glucopyranosyl-\u3b2-digitalopyranoside) (5), and two new hemiterpenoids, (4R)-4-hydroxy-3-isopropylpentyl \u3b2-rutinoside (6) and (R)-2-ethyl-3-methylbutyl \u3b2-rutinoside (7), together with two known phenylpropanoids and a known phenylethanoid. The isolated cardenolides strongly inhibited the proliferation of the HT-1080 cell line (IC50 values, 54 121600 nM).Peer reviewed: YesNRC publication: N